Limited Rate Research Articles

Experimental investigation of the impact of different flame holder materials on the flame stability and flame characteristics using double-layered combustor wall material

This paper investigates the effects of different thermal conductivity flame holder materials with different blockage ratios to optimise flame stabilisation, blow-off limits and recirculation zone inside the combustor wall of a premixed LPG and air. The paper experimentally investigates the performance of flame holders are using three different materials such as ceramic flame holder, stainless steel flame holder and silicon carbide flame holder. The study aims to measure the blow-off limits, equivalence ratio, LPG mass flow rate, rich and lean flammability limits, and blow-off regions that impact flame stability and stable flames. The impact of disc-shaped materials having different blockage ratios such as 0.26, 0.36, 0.46, 0.56, respectively are investigated at an equivalence ratio of 1.80 and mass fuel flow rate of 0.61 g/s. The double-layered combustor having higher thermal conductivity for the inner wall and lower thermal conductivity material for the outer wall significantly reduces the heat loss to the surroundings. The study implies were the important implementation of wall material type, flame holder material type, optimal blockage ratio, flame stability of LPG and air-premixed flame, and mass fuel flow rate for attaining successful combustion. The results indicate that the lower thermal conductivity flame holder material along with the help of high and low double-layered wall material, optimal blockage ratio can induce a stable flame region and recirculation zone. The blockage ratio at 0.46 performed well in flame stabilisation, decreased flame length and also in flame shape. The flame species concentrations such as CO, NO, CO2, and O2 were analysed by using a Portable gas analyser. The results influence a better study of the performance of the different material-based flame holders.

P-1177. Impact of Staphyloccocus aureus Surveillance and Decolonization on MRSA and MSSA Infections in a Neonatal Intensive Care Unit

Abstract Background Staphyloccus aureus (SA) infection causes significant morbidity and mortality in NICU patients. Colonization by SA is a risk factor for infection. Surveillance and decolonization aims to curb the transmission of SA isolates thereby reducing rates of SA infection. Figure 1. Epidemic Curve of MRSA Colonization and Infections 2012-2023 Methods This retrospective study from 2012-2023 takes place in a 42-bed level-three NICU in Texas Children’s Hospital (Houston, Texas). Neonates are admitted to a private room and undergo weekly surveillance from admission/birth until discharge. Surveillance cultures for MRSA and subsequent decolonization of MRSA-positive neonates began in Oct. 2016. MRSA surveillance was changed to PCR (with reflex to culture if positive) in June 2017. Surveillance PCR (with reflex to culture if positive) and decolonization for MSSA began in Oct. 2021. Colonization is defined as detection by PCR or isolation by culture of SA from nares, umbilicus, or groin. Colonized neonates are treated with mupirocin twice daily for five days and if at least 4 weeks chronologic age or 36 weeks gestational age, topical 2% chlorhexidine wipes daily for five days. Infection is defined by the isolation of SA from cultures in the context of illness. Multiple positive specimens from the same site are considered the same infection if isolated within a 14-day window. Epidemic curves compare colonization and infections before and after the protocol. This study was approved by the Baylor College of Medicine Institutional Review Board. Figure 2. Epidemic Curve of MSSA Colonization and Infections 2012-2023 Results Surveillance and decolonization of MRSA-colonized neonates reduced the number of MRSA infections from its peak in 2016 (Figure 1). We continue to see SA-colonized infants especially with a substantial MSSA colonization burden. Despite the high rate of MSSA colonization, the number of MSSA infections remains low (Figure 2). Control charts (Figure 3 and 4) demonstrate rate, mean and upper limit of infection rates calculated per 1000 patient days. Figure 3. Control Chart for MRSA Infections Conclusion The implementation of surveillance and targeted decolonization has been shown to decrease the number of MRSA infection even with ongoing colonization. Despite the high burden of MSSA-colonization, we do not see major peaks of MSSA infections. Further studies should explore if the presence of resistance genes to mupirocin and/or chlorhexidine explains ongoing colonization. Figure 4. Control Chart for MSSA Infections Disclosures All Authors: No reported disclosures

Accuracy of remote, video-based supraventricular tachycardia detection in patients undergoing elective electrical cardioversion: a prospective cohort.

Unobtrusive pulse rate monitoring by continuous video recording, based on remote photoplethysmography (rPPG), might enable early detection of perioperative arrhythmias in general ward patients. However, the accuracy of an rPPG-based machine learning model to monitor the pulse rate during sinus rhythm and arrhythmias is unknown. We conducted a prospective, observational diagnostic study in a cohort with a high prevalence of arrhythmias (patients undergoing elective electrical cardioversion). Pulse rate was assessed with rPPG via a visible light camera and ECG as reference, before and after cardioversion. A cardiologist categorized ECGs into normal sinus rhythm or arrhythmias requiring further investigation. A supervised machine learning model (support vector machine with Gaussian kernel) was trained using rPPG signal features from 60-s intervals and validated via leave-one-subject-out. Pulse rate measurement performance was evaluated with Bland-Altman analysis. Of 72 patients screened, 51 patients were included in the analyses, including 444 60-s intervals with normal sinus rhythm and 1130 60-s intervals of clinically relevant arrhythmias. The model showed robust discrimination (AUC 0.95 [0.93-0.96]) and good calibration. For pulse rate measurement, the bias and limits of agreement for sinus rhythm were 1.21 [- 8.60 to 11.02], while for arrhythmia, they were - 7.45 [- 35.75 to 20.86]. The machine learning model accurately identified sinus rhythm and arrhythmias using rPPG in real-world conditions. Heart rate underestimation during arrhythmias highlights the need for optimization.

Range shifts as drivers of niche breadth and dispersal ability in wild populations.

Research Highlight: Edwards, O. M., Zhai, L., Reichert, M. S., Shaughnessy, C. A., Ozment, L., & Zhang, B. (2024). Physiological and morphological traits affect contemporary range expansion and implications for species distribution modelling in an amphibian species. Journal of Animal Ecology, https://doi.org/10.1111/1365-2656.14212. Range expansion can have profound ecological and evolutionary consequences that feedback on the expansion process itself. With global climate change causing widespread species range shifts to higher latitudes and altitudes, it is essential that we better understand these dynamics during native range expansion in the wild. In a recent study on poleward-spreading treefrogs (Hyla cinerea), Edwards etal. (2024) measured how morphological and physiological traits differed between populations from the recently expanded and historic range. They found that range-edge frogs had increased cold tolerance and longer legs associated with better dispersal, which could strongly affect the rate and geographic limits of expansion. Edwards etal. then show how species distribution models fit separately to the historic and expanded range more accurately predict habitat suitability near the historic range boundary. This paper provides a timely and compelling example of rapid differentiation in dispersal and niche traits during native range expansion, and explores ways in which we can model species range shifts while accounting for this phenotypic variation in space and time.

Stabilizing a Bio-Inspired Rotating Empennage Fighter Aircraft in Multiple Trim Scenarios

This paper considers the problem of stabilizing a bio-inspired fighter aircraft at its Air Combat Maneuver Condition in steady-level and coordinated-turning flight. The aircraft equations of motion are linearized, and an infinite-horizon linear quadratic regulator design is conducted. The open-loop system is unstable in the short-period and Dutch roll modes. This is mitigated in the closed-loop system, which is analyzed in the time and frequency domains. Included in the simulation dynamics are first-order actuator models, actuator deflection limits, and actuator rate limits. These are particularly important for this bio-inspired aircraft because control actuation requires rotation of the empennage, which has relatively large inertia. Simulation responses to initial condition dispersions, aerodynamic model error, and atmospheric turbulence are analyzed to characterize time-domain properties: settling time, region of attraction, control saturation, and robustness. Due to poor singular values for the throttle setting and rotating tail inputs, analysis is dedicated to control designs with these inputs fixed at trim values. Within the scope of these analyses, fixing the rotating tail at trim does not significantly degrade system performance.

Reliability and Accuracy of the Fitbit Charge 4 Photoplethysmography Heart Rate Sensor in Ecological Conditions: Validation Study.

Wrist-worn photoplethysmography (PPG) sensors allow for continuous heart rate (HR) measurement without the inconveniences of wearing a chest belt. Although green light PPG technology reduces HR measurement motion artifacts, only a limited number of studies have investigated the reliability and accuracy of wearables in non-laboratory-controlled conditions with actual specific and various physical activity movements. The purpose of this study was to (1) assess the reliability and accuracy of the PPG-based HR sensor of the Fitbit Charge 4 (FC4) in ecological conditions and (2) quantify the potential variability caused by the nature of activities. We collected HR data from participants who performed badminton, tennis, orienteering running, running, cycling, and soccer while simultaneously wearing the FC4 and the Polar H10 chest belt (criterion sensor). Skin tone was assessed with the Fitzpatrick Skin Scale. Once data from the FC4 and criterion data were synchronized, accuracy and reliability analyses were performed, using intraclass correlation coefficients (ICCs), Lin concordance correlation coefficients (CCCs), mean absolute percentage errors (MAPEs), and Bland-Altman tests. A linear univariate model was also used to evaluate the effect of skin tone on bias. All analyses were stratified by activity and pooled activity types (racket sports and running sports). A total of 77.5 hours of HR recordings from 26 participants (age: mean 21.1, SD 5.8 years) were analyzed. The highest reliability was found for running sports, with ICCs and CCCs of 0.90 and 0.99 for running and 0.80 and 0.93 for orienteering running, respectively, whereas the ICCs and CCCs were 0.37 and 0.78, 0.42 and 0.88, 0.65 and 0.97, and 0.49 and 0.81 for badminton, tennis, cycling, and soccer, respectively. We found the highest accuracy for running (bias: 0.1 beats per minute [bpm]; MAPE 1.2%, SD 4.6%) and the lowest for badminton (bias: -16.5 bpm; MAPE 16.2%, SD 14.4%) and soccer (bias: -16.5 bpm; MAPE 17.5%, SD 20.8%). Limit of agreement (LOA) width and artifact rate followed the same trend. No effect of skin tone was observed on bias. LOA width, bias, and MAPE results found for racket sports and soccer suggest a high sensitivity to motion artifacts for activities that involve "sharp" and random arm movements. In this study, we did not measure arm motion, which limits our results. However, whereas individuals might benefit from using the FC4 for casual training in aerobic sports, we cannot recommend the use of the FC4 for specific purposes requiring high reliability and accuracy, such as research purposes.

Author’s Reply to ‘Comment on “Dynamic surface control of trajectory tracking marine vehicles with actuator magnitude and rate limits” [Automatica 105 (2019) 433–442]’

Author’s Reply to ‘Comment on “Dynamic surface control of trajectory tracking marine vehicles with actuator magnitude and rate limits” [Automatica 105 (2019) 433–442]’

Probing dark relativistic species and their interactions with dark matter through CMB and 21 cm surveys

We investigate the sensitivity of the 21 cm power spectrum from cosmic dawn and the epoch of reionization to models of free-streaming dark radiation (parameterized through N eff) and interacting dark radiation-dark matter models (DM-DR). The latter models have gained attention for their potential in addressing recent cosmological tensions and structure formation challenges.We perform a Fisher matrix analysis under different assumptions regarding the astrophysical modeling, and forecast the sensitivity of HERA observations, combined with CMB data from Planck and the Simons Observatory (SO), to N eff and DM-DR interaction modeled using the ETHOS framework assuming a constant scattering rate between the two components.Most importantly, we find that 21 cm observations can improve the sensitivity to the DM-DR interaction rate by up to four order of magnitude compared to Planck and SO. Conversely, in the limit of low interaction rate (which asymptotically matches N eff), CMB data dominates the constraining power, but the inclusion of HERA data can provide a ∼ 20% improvement in sensitivity over CMB data alone.Moreover, we find that HERA observations will be able to probe a region of the DM-DR interaction parameter space which is promising to explain the weak lensing amplitude `S 8' tension. Our results demonstrate the complementarity of 21 cm and CMB data in exploring dark sector interactions.

Approaching building lifetimes and hazard rates through demolition patterns: Case studies for a historical city center

AbstractDespite their relevance in building stock modeling, building lifetimes are poorly understood and tend to form the weakest link in forecasting energy use, greenhouse gas (GHG) emissions, waste generation, and resource use. Here, we develop a methodology to trace building lifetimes for cohorts in two central areas built up after fires in the 1840s. Using Geographical Information System (GIS) data of the current building stock and archival material, we determined yearly hazard rates for buildings within the cohort 1841–1845 in the historical center of Trondheim, Norway. We find that hazard rates are very sensitive to events ranging from global to hyperlocal scales and that demolition rates have slowed down significantly since the 1980s when municipal preservation policies came into effect. In contrast, age‐based lifetime approaches fail to capture the effects of such events as they only account for the delay between construction and demolition. We discuss the use and limitations of hazard rates to better reflect changes in demolition that are not correlated with building age. Our study underscores that building lifetimes are a property of a wider system rather than an attribute of individual structures. In that sense, hazard rates are a more suitable approach to capture spatiotemporal changes of building stocks and could be further used in scenarios in dynamic models. This article met the requirements for a gold‐gold JIE data openness badge described at http://jie.click/badges.

Research on the Fast Charging Strategy of Power Lithium-Ion Batteries Based on the High Environmental Temperature in Southeast Asia

To address the problem of excessive charging time for electric vehicles (EVs) in the high ambient temperature regions of Southeast Asia, this article proposes a rapid charging strategy based on battery state of charge (SOC) and temperature adjustment. The maximum charging capacity of the cell is exerted within different SOCs and temperature ranges. Taking a power lithium-ion battery (LIB) with a capacity of 120 Ah as the research object, a rapid charging model of the battery module was established. The battery module was cooled by means of a liquid cooling system. The combination of the fast charging strategy and the cooling strategy was employed to comprehensively analyze the restrictions of the fast charging rate imposed by the battery SOC and temperature. The results indicate that when the coolant flow rate was 12 L/min and the inlet coolant temperature was 22 °C, the liquid cooling system possessed the optimal heat exchange capacity and the lowest energy consumption. The maximum temperature (Tmax) of the battery during the charging process was 50.04 °C, and the charging time was 2634 s. To lower the Tmax of the battery during the charging process, a charging rate limit was imposed on the temperature range above 48 °C based on the original fast charging strategy. The Tmax decreased by 0.85 °C when charging with the optimized fast charging strategy.

Small and Close-in Planets are Uncommon Around A-type Stars

Abstract The Kepler and K2 missions enabled robust calculations of planet occurrence rates around FGKM-type stars. However, these missions observed too few stars with earlier spectral types to tightly constrain the occurrence rates of planets orbiting hotter stars. Using TESS, we calculate the occurrence rate of small (1 R ⊕ < R p < 8 R ⊕), close-in (P orb < 10 days) planets orbiting A-type stars for the first time. We search a sample of 20,257 bright (6 < T < 10) A-type stars for transiting planets using a custom pipeline and vet the detected signals, finding no reliable small planets. We characterize the pipeline completeness using injection–recovery tests and determine the 3σ upper limits of the occurrence rates of close-in sub-Saturns (4 R ⊕ < R p < 8 R ⊕), sub-Neptunes (2 R ⊕ < R p < 4 R ⊕), and super-Earths (1 R ⊕ < R p < 2 R ⊕). We find upper limits of 2.2 ± 0.4 sub-Saturns and 9.1 ± 1.8 sub-Neptunes per 1000 A-type stars, which may be more than 3× and 6× lower than Kepler-era estimates for Sun-like stars. We calculate an upper limit of 186 ± 34 super-Earths per 1000 A-type stars, which may be more than 1.5× lower than that for M dwarfs. Our results hint that small, close-in planets become rarer around early-type stars and that their occurrence rates decrease faster than that of hot Jupiters with increasing host star temperature. We discuss plausible explanations for these trends, including star–disk interactions and enhanced photoevaporation of planet atmospheres.

PDS 70b Shows Stellar-like Carbon-to-oxygen Ratio

Abstract The ~5 Myr PDS 70 is the only known system with protoplanets residing in the cavity of the circumstellar disk from which they formed, ideal for studying exoplanet formation and evolution within its natal environment. Here, we report the first spin constraint and C/O measurement of PDS 70b from Keck/KPIC high-resolution spectroscopy. We detected CO (3.8σ) and H2O (3.5σ) molecules in the PDS 70b atmosphere via cross correlation, with a combined CO and H2O template detection significance of 4.2σ. Our forward-model fits, using BT-Settl model grids, provide an upper limit for the spin rate of PDS 70b (<29 km s−1). The atmospheric retrievals constrain the PDS 70b C/O ratio to 0.28 − 0.12 + 0.20 (<0.63 under 95% confidence level) and a metallicity [C/H] of − 0.2 − 0.5 + 0.8 dex, consistent with that of its host star. The following scenarios can explain our measured C/O of PDS 70b in contrast with that of the gas-rich outer disk (for which C/O ≳ 1). First, the bulk composition of PDS 70b might be dominated by dust+ice aggregates rather than disk gas. Another possible explanation is that the disk became carbon enriched after PDS 70b was formed, as predicted in models of disk chemical evolution and as observed in both very low-mass stars and older disk systems with JWST/MIRI. Because PDS 70b continues to accrete and its chemical evolution is not yet complete, more sophisticated modeling of the planet and the disk, and higher-quality observations of PDS 70b (and possibly PDS 70c), are necessary to validate these scenarios.

Application of Sooty Tern Optimization Algorithm on Solar‐Wind‐Battery‐Thermal Integrated Dynamic Economic Emission Dispatch Problems

ABSTRACTThe current challenges faced by conventional power plants, including increasing load demand over time, high generation costs, and excessive emissions from fossil fuels, have been helped to overcome by the integration of renewable energy sources (RESs) alongside conventional thermal power units. In this article, traditional dynamic economic emission dispatch (DEED) is enhanced by incorporating RESs, including two solar units, two wind units, and one battery power unit, forming the solar‐wind‐battery‐thermal (SWBT) integrated DEED (SWBTDEED). This integration aimed at reducing generation costs and minimizing excessive fuel emissions, and combining cost and emissions over a 24 h period. Four different test systems, each incorporating 6, 10, 30, and 40 thermal units alongside the same RESs, are considered to meet varying load demands hourly throughout the day. This article demonstrates that, in addition to reducing generation costs, SWBTDEED is capable of reducing emissions by 38.28%, 28.48%, 20.67%, and 20.44% for four test systems, thereby protecting the environment. The sooty tern optimization algorithm (STOA) is proposed in this article for solving complex DEED and SWBTDEED problems, considering various constraints such as generation limits, ramp rate limits, valve point loading, and Weibull distribution. Finally, the robustness, optimization efficiency, and capability of the STOA technique in handling complex nonlinear constraints are demonstrated in the results section, showcasing its ability to achieve optimal results compared to other algorithms such as the sine‐cosine algorithm, backtracking search algorithm, differential evolution, and particle swarm optimization.

Determination and description of a vehicle's maximum jerk capacity

Both Transient Optimal and Quasi-Steady-State vehicle modelling are frequently used for minimum time manoeuvre and minimum lap-time simulations for motorsport/vehicle development purposes. Quasi-Steady-State methods have been shown to perform such tasks with low computational cost but produce results with measurable deviation from equivalent Transient Optimal studies. It is hypothesised that bounding point-mass models with jerk limits will improve alignment with Transient Optimal simulations through the consideration of transient behaviours such as control application rates and inertia. This work presents a new method for the determination of a vehicle's maximum jerk capacity from a seven degree-of-freedom vehicle model. A range of results from this proposed technique are presented and show the sensitivity of jerk capacity to changes in control application rate limits and yaw inertia, as well as current vehicle velocity, acceleration, and jerk. It is proposed that further exploration of the validity of the jerk limit calculation method take place through characterisation of said limits and application to a point-mass model, after which comparison to Transient Optimal and Quasi-Steady-State equivalents can occur.

Middle segment preserving pancreatectomy versus total pancreatectomy: a comparative analysis of short- and long-term outcomes.

Middle-segment preserving pancreatectomy (MSPP) serves as an alternative to total pancreatectomy (TP) for preserving the pancreatic body in multifocal pancreatic neoplasms. Despite the potential benefits of TP, the detailed short- and long-term prognoses remain unclear. We evaluated the feasibility of MSPP by comparing the perioperative outcomes and postoperative endocrine and exocrine functions with those of TP. The study included 10 TP and 7 MSPP patients. Patients with pancreatic ductal adenocarcinoma and invasive intraductal papillary mucinous carcinoma were excluded. MSPP was associated with a high incidence (57.1%) of postoperative pancreatic fistula (POPF); however, there were no cases of post-pancreatectomy hemorrhage or postoperative mortality in any group. The postoperative hospital stay and readmission rates were comparable between the groups. At 1year postoperatively, MSPP reduced the risk of new-onset insulin-dependent diabetes mellitus, maintained good glycemic control with minimal hypoglycemic events, and preserved skeletal muscle, subcutaneous fat, and visceral fat. One patient in the MSPP group with a neuroendocrine tumor had postoperative recurrence in the para-aortic lymph node. Despite the high POPF rate and oncologic limitations, MSPP showed superior long-term outcomes in glycemic control and preservation of body composition. MSPP may be an acceptable treatment option for selected patients.

Performance Analysis of Parallel Free-Space Optical/Radio Frequency Transmissions in Satellite–Aerial–Ground Integrated Network with Power Allocation

Satellite–aerial–ground integrated networks (SAGINs) combined with hybrid free-space optical (FSO) and radio frequency (RF) transmissions have shown great potential in improving service throughput and reliability. The coverage mismatch and rate limitation of traditional hybrid FSO/RF design have restricted its development. In this paper, we investigate the performance of parallel FSO/RF transmissions in SAGIN, taking into account the effect of weather conditions and the quality of service (QoS) of ground users. A three-hop relay system is proposed, where the FSO and RF links jointly provide services to ground users in remote areas. Specifically, considering the limited transmit power of the relay node, we have studied the optimal power allocation between parallel FSO and RF links to further improve system energy efficiency. The performance of the proposed system is evaluated in terms of capacity outage probability, weighted average bit-error rate (BER), and energy efficiency. Moreover, asymptotic capacity outage probability is also derived to obtain more engineering insights. Finally, numerical results show that the energy efficiency of the proposed parallel scheme improves by 30.9% compared to only the FSO scheme at a total transmit power of 15 dBW.

Exploring seismic warning thresholds for vehicle-track systems through combined shaking table tests and dynamic numerical simulations

This study conducted vehicle-track shaking table model tests at the Seismic Laboratory of the China Academy of Building Research, employing both unidirectional (horizontal) and bidirectional (horizontal and vertical) seismic waves. Discussions were made on the dynamic response of the vehicle-track system and the mechanism of derailment, providing data support for the research on seismic early warning thresholds for vehicles. Additionally, three-dimensional finite element numerical simulations were performed on the vehicle-track dynamic model, successfully incorporating track irregularities into the model. In this paper, the main conclusions are as follows: The limits of the wheel load reduction rate and that of the derailment coefficient specified in China’s national standard “Code for Dynamic Performance Evaluation and Test Identification of Railway Vehicles” are conservative. The primary cause of vehicle derailment was identified as horizontal vibration of the track structure induced by seismic activity. Different seismic waves have varying effects on the dynamic response of the vehicle-track model, necessitating further research on the impact of seismic wave spectrum characteristics on vehicle safety during operation. When horizontal and vertical seismic waves are simultaneously applied, horizontal seismic waves have a greater impact on dynamic response. The numerical simulation results align well with experimental results, confirming the accuracy of the vehicle-track dynamic numerical model. It is recommended to adopt a more conservative seismic early warning threshold of 0.04 g to ensure the safety of train operation.

Development of a CLYC-based wide dose rate range portable neutron-gamma detector.

This paper describes the development of a portable neutron-gamma detector for environmental radiation monitoring based on the CLYC crystal. It can function as a gamma spectrometer, gamma dosimeter, and thermal neutron counter. The upper measurement limit of gamma dose rate is approximately 6 mSv/h by using the proposed current mode in CLYC crystal and PMT. Meanwhile, the detector has a gamma energy resolution of 4.86% at 662 keV, and a figure of merit (FOM) of 3.32±0.04 for gamma and neutron pulse shape discrimination. In the initial phase of applications, the detector was used to measure the gamma and neutron radiation levels around the beamline of the associated Proton beam Experiment Platform (APEP) and R-dump room at the China Spallation Neutron Source (CSNS).

Optimizing reserve-constrained economic dispatch: Cheetah optimizer with constraint handling method in Static/Dynamic/Single/ Multi-Area Systems

Managing the power-generating units on the horizon of one-day scheduling considering all practical equality, inequality, and realistic constraints has always been a significant challenge in power systems. The constraints, such as valve-point effects, prohibited operation zones, transmission losses, and ramp rate limits corresponding to dynamic economic dispatch, change the optimization problem to a complex, nonlinear, non-smooth, high-dimensional, and non-convex one. Therefore, an efficient algorithm and a suitable constraint handling method are needed to solve practical constrained dynamic economic dispatch (DED). This paper proposes a newly developed Cheetah optimizer (CO) that coincides with a backward-forward constraint handling method to tackle the optimum operational cost. The CO algorithm’s performance is verified using eight DED and ED test cases from five different systems. The suggested technique is compared with several state-of-the-art optimization algorithms regarding the effectiveness of achieved results. Numerical results evaluate the performances of the CO advantages on the benchmarks and the DED cases where the results of 5-,10- and 30-unit systems are enhanced in different cases. To achieve a higher level of realism in modeling the ED and DED problem, adopting a multi-area DED (MADED) approach has emerged as a promising strategy. In this paper, three distinct cases of MAED and MADED problems are investigated to demonstrate the effectiveness of the proposed method. Specifically, in cases involving DED-10 and 30 units, two-area 40 units ED, and four-area 40 units DED, significantly improved solutions were obtained compared to previous studies.

CAUSES AND EFFECT OF COMMUNITY INSTABILITY ON SOCIO-ECONOMIC ACTIVITIES OF THE PEOPLES OF BORNO STATE, NIGERIA

This paper examines the causes and implications of Boko Haram insurgency on socio-economic activities of the people’s of Borno State, Nigeria. Available factors advanced in the process of the study helped understand what motivating people to join the Boko Haram sect in Borno State and other states of the North-eastern region of Nigeria. It is no longer a news that Boko Haram in the waves of their insurgency in Borno State recorded a killing of thousands of innocent’s people, while destroyed and burnt down government and public properties and infrastructures worth Billions of Naira. Besides, the Boko Haram continued indiscriminate attacks pushed millions of people to internally displaced persons camps and forced thousands of business men and women to abandon their businesses thereby created an unprecedented joblessness, hunger and abject poverty in Maiduguri Borno State. However, it is evident that schools of all level were temporarily closed in the mid of the insurgency for certain period, while public health centres were equally closed in some local government areas due to the pressure of the Boko Haram indiscriminate attacks and killings. All efforts by the security agents to cease the Boko Haram insurgency activities failed to yield positive result. However, little or no attention has been given to the negative consequences of the Boko Haram insurgency on socio-economic activities of the people of Borno State. Its against this backdrop, this paper is intended to study the implications of the Boko Haram insurgency activities on socio-economic activities of the peoples of Borno State. Five objectives, two hypotheses were raised to answer the study questions to comprehend the work. A qualitative research design is adopted using primary and secondary sources of data collection method to generates and adequate information on what influenced the peoples to pledges allegiance to Boko Haram sect, and to what extent the Boko Haram insurgency activities affected the peoples socio-economic activities. A purposive sampling technique is used to select the study respondents. The study target population was drawn from two senatorial districts of Borno State. Borno Central Senatorial District and Northern Borno Senatorial District respectively. Four local government areas were chosen from the two senatorial zones, two each, these are Maiduguri Metropolis, Bama LGA, Kukawa LGA and Mobbar LGA. A sampling size of 379 respondents were selected, 95 respondents from each of the four local government areas chosen. A descriptive statistic, mean and standard deviation as adopted using upper and lower limits of decision rate of 3.0 mean coupled with 5 Likert scale method were utilized to analyze the data and interpret the results. The results of the study revealed that the community instability caused by Boko Haram insurgency in Borno State has posed a serious threat to all sectors of human endeavors, includes, education, healthcare, agriculture and specifically paralyzed the socio-economic activities of the peoples of Borno State. The paper concluded that the damages have been done to almost all the sectors of human endeavors by the activities of Boko Haram insurgency hence the need for investing efforts to revive the areas affected, such as education, healthcare delivery, agriculture and so on. However, this paper is equally recommended that the local governments, state and federal government as well as national and international non-governmental organization and philanthropist should as a matter of urgency join hands together and assist the victims of the Boko Haram insurgency displaced from their business activities and ensuring that all affected sectors of human endeavor are effectively functioning. It is also recommended that government should come up with plan to regulates the affairs of both Islamic and Christianity to avoid radicalization of our growing youth in the future.